The Year of Food Fights: Contention in the Dietary Community

Experts have been busy since the dietary guideline recommendations dropped in February

MedPage Today is republishing one of the most important stories in endocrinology from 2015, which looked at experts' responses to the controversial panel recommendations for the 2015 dietary guidelines. The controversy is still very much alive, and the following is a look at what has happened since that story. The guidelines are expected to be released within a few weeks.

Those who have followed this year's debate over the government's forthcoming revision of dietary guidelines might be forgiven for thinking that wherever there are four nutrition experts gathered together, there will be at least five opinions.

Ever since the Dietary Guidelines Advisory Committee made their recommendations public in February of this year, there's been no shortage of attacks, controversies, and even praise. (The 2015 recommendations received 15 times more comments than in 2010.) And this week, even Congress got involved by calling for a comprehensive -- and expensive, at about $1 million -- review of the process for developing the dietary guidelines.

This year there was a shift in how the advisory panel approached healthy eating. "There is a shift towards focusing on healthy dietary patterns including more plants (fruits and vegetables), and this tends to be agreed upon by the majority of groups," said Spencer Nadolsky, DO, a family and obesity medicine doctor in Maryland.

The panel, which meets every 5 years, makes the recommendations to the U.S. Department of Agriculture and the Department of Health and Human Services, which then jointly form the guidelines.

Fat Food Fights

The most significant changes will likely happen around dietary fat. For decades, the guidelines limited total fat intake, but in June, researchers argued that the limitation could actually be detrimental, since both saturated and unsaturated fats were lumped together. In addition, saturated fats themselves have been wrongly vilified, argue some researchers. And in fact, a growing body of research indicates that saturated fats might not be as bad as previously thought.

Saturated fats were also the topic of one of the more significant rows since the committee released their recommendations. In September, journalist and author Nina Teicholz wrote in the BMJ that the dietary guidelines used "weak scientific standards" and relied on old data to make its recommendations on saturated fats. But shortly after it was released, TheVergecalled the BMJ's investigation "bogus" and pointed out Teicholz' conflicts of interests, which include publication of a book looking at how fats came to be vilified. And scores of prominent nutrition and cardiovascular scientists -- nearly 200 in all -- signed a petition calling for the BMJ to retract the piece.

The BMJ stood by the article, but did eventually add a correction to one of its points. Aaron Carroll, MD, at Indiana University, a frequent contributor to the New York Times and author at The Incidental Economist, wrote in the Times that the BMJ report was too confident in some of its statements, but it was also correct in parts. "We have, for too long, made decisive proclamations based on research that did not support them," he wrote. But he added that this new round of guidelines are far more evidence-based than in years past.

Perhaps one of the main takeaways from all of this, added Carroll, is that with charges of conflicts of interest coming from all sides, with fad diets, and with less-than-ideal research in many areas, nutritional research can be exceptionally charged.

Sweet Praise

A less controversial recommendation from the committee was that added sugars be limited to a maximum of 10% of total calories per day. For most adults, that's about 12 teaspoons a day. The panel also suggested that sugar drinks be removed from schools and endorsed a proposed FDA rule that would make the reporting of added sugars on food nutrition labels mandatory.

Three documentaries detailing the adverse effects of sugar were released this year, and sugar is increasingly being blamed for its role in a number of health conditions, and particularly for type 2 diabetes and metabolic disease.

But in the time since the recommendations were released, the topic hasn't been entirely free of controversy -- there has been significant debate this year over "sugar taxes," for example. A 10% soda tax in Mexico appears to be reducing consumption, but the only place in the U.S. to adopt the tax is Berkeley, Calif. Sodas -- along with energy drinks, sugary juices, and sweet tea -- are taxed at a penny an ounce there, an amount some have suggested isn't significant enough to change consumption patterns. Since the sugar industry has been subsidized for decades in the U.S., it might not make sense to have a tax, a researcher pointed out to MedPage Today earlier this year.

There's also been significant lobbying from the sugar industry and companies like Coca-Cola with sugary products. But the committee that makes the guidelines is likely to go along with the recommendations -- they almost always have in years past -- which could eventually lead to less consumption of sugary products.

Salt & Cholesterol

There's been growing doubt about the government's advisement that Americans are eating too much salt. The same goes for cholesterol. Both issues are contentious, but the latest research appears to contradict -- or at least complicate -- the picture. The American Heart Association continues to insist that the current recommendation -- a limit of 2,300 milligrams of sodium per day -- is correct.

But that's not the consensus: some think that the recommendation rests on flimsy evidence, and recent studies have called into question the supposedly clear link between hypertension and sodium. The authors of the new limitation are likely to follow the recommendation and keep the limit at 2,300 milligrams.

But when it comes to cholesterol, the panel reversed long-standing policy and recommended that the limit on dietary cholesterol be removed. Lifting of the cap has been something that many people "have argued for years now," said Nadolsky. "Physiologically, most people won't have increases in serum cholesterol when ingesting more cholesterol from foods," he added. "Because of this, it was felt to not be a nutrient of concern."

A Limited Science

Part of the reason for the continued debates in these areas is that good dietary research is hard to come by. Many of the studies used by the advisory panel rely on data from the National Health and Nutrition Examination Survey (NHANES), which uses food frequency questionnaires that depend on the respondent's memory to determine what was eaten. But that method can be wildly inaccurate, MedPage Today reported earlier this year, and a study showed that people often reported an intake that wasn't even physiologically plausible.

Some researchers interviewed for that story had concerns of conflict of interest, and there's been a back-and-forth between scientists. Earlier this month, Edward Archer, PhD, at the University of Alabama at Birmingham, the author of the original study, wrote in Mayo Clinic Proceedingsthat in the 2015 advisory committee's report "the words association, associated, and relationship are used more than 900 times ... whereas the words causal and causality are used fewer than 30 times and not once to describe an actual causal diet-health relationship."

He added that the hypothesis that memory-based methods can provide reasonable estimates of dietary intakes on both the national and group level has been "strongly refuted." But Archer's opinion isn't a popular one, as earlier reporting showed.

In an email to MedPage Today, Karl Nadolsky, DO -- the other Nadolsky brother and also an endocrinologist in Maryland -- wrote, "While the nutritional scientific community still has some areas of uncertainty and stirs debate between groups with strong opinions, the trend continues to have guidelines and recommendations coalesce around important topics with good evidence."

"There remains contention on the periphery because nutritional science is difficult to pin down and we have to rely on big observational studies which are far from perfect and often give opportunity for proponents of discordant philosophies fodder for debate," he said. "But overall I do think there is more consensus for guiding patients toward eating whole foods and decreasing refined/processed foods which can fit and incorporate many different dietary paradigms from plant-based philosophies to Mediterranean diets, etc."

The guidelines are expected to be released soon. The last set were issued at the end of January.

UPDATE: MPT received the following response from Nina Teicholz:

I’m very grateful to Medpage Today for allowing me the chance to provide some greater context for the BMJ article.

The BMJ article was controversial because it asserted that the 2015 Dietary Guidelines Advisory Committee had not comprehensively reviewed the best and most current science on key topics, including whether saturated fats cause heart disease. The article generated quite a bit of news coverage, which I’ve posted here.

I wrote to Medpage, asking them to provide some balance to the quote by the reporter for The Verge. Citing the exceptionally negative opinion of a reporter who had never before covered nutrition does not seem justifiable, especially when there were many more neutral or even supportive comments made by experts in the field, cited in news stories and/or submitted in Rapid Responses to BMJ. For example, Cardiobrief reported top nutrition expert Arne Astrup saying, “The [DGA expert] committee seems to be completely dissociated from the top-level scientific community, and unaware of the most updated evidence.”

I wanted also to clarify the numbers of people signing the BMJ retraction letter. When the Center for Science in the Public Interest (CSPI) originally publicized its retraction letter on November 5th, signees included more than 180 experts from the fields of nutrition, cardiovascular disease, and environmental science, as well as some management consultants and graduate students. On December 17, the CSPI Retraction request was officially published by BMJ as a Rapid Response. According to independent researchers who have taken an interest in this story, 18 signers from the original list withdrew their names from the retraction letter, leaving 173. While the motives for withdrawal might be interesting, the numbers overall are still extremely large, and lead one to question why so many names were needed for such a letter; when a pamphlet was published entitled “100 Authors Against Einstein,” Einstein retorted, “If I were wrong, one would be enough.”

Had I been contacted by MedPage for a response to its article, I would have noted that the 11 alleged inaccuracies in my BMJ article as alleged by CSPI address nine facts in the article and two facts in the supplementary materials (of the overall 700+ facts in the article and supplementary materials). My complete response to these 11 allegations is here. The allegations do not, in this analysis, appear to be substantial. Two of the allegations, for example, were already addressed in my original Rapid Response. One allegation by CSPI presents no point of fact.

In response to Medpage’s repetition of The Verge’s claim my book is a conflict of interest for the BMJ article, I believe it is unfair to single out my book as a particular conflict of interest when other experts with published books are routinely cited by Medpage without noting this type of conflict. Moreover, the Dietary Guidelines committee members members whose work I critique in the BMJ article have published, between them, more than nine popular diet books. Fair journalism would note these types of conflicts on all sides.

This story, originally published on Dec. 27 at 15:00, has been updated.

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